Tumors Of The Lung Flashcards
Lung tumors general statistics
95% of the tumors are adeno or non adeno carcinomas (epithelial linage)
5% are carcinoid, mesenchymal, lymphomas or benign lesions
Peak incidence of lung cancer is 50-60 yrs
At diagnosis, 50% of Patients already have metastasis to distal regions past lymph nodes
- 25% of the total lung cancers have metastasis only to the regional lymph nodes
Prognosis is poor in all lung cancers
Most common benign lung tumor is what?
Haramtoma “coin lesion”
- constricts of mature cartilage, fat, fibrous tissue and blood vessels
What is the most important cause of cancer-related deaths?
Carcinoma of the lung
- both male and female
- is decreasing in men and increasing in women
4 major histologic types of carcinoma in the lungs
Adenocarinoma
- strong association with smoking
- most common lung tumor in women and people under 45 yrs old
Squamous cell carcinoma
- strong association with smoking
Large cell carcinoma
Small cell carcinoma
- strong association with smoking
- almost always metastasis by diagnosis time
Etiology and pathogens is of lung carcinomas
All arise by a stepwise accumulation of driver mutations
The order of driver mutations can be varied however the following two things are most common (is NOT random though):
- TP53 tumor suppressor gene and KRAS oncogene are mutated pretty late
- 3p tumor suppressor genes are mutated pretty early
EGFR adenocarcinomas
A subset of adenocarcinomas that is common in nonsmoking women of Asian descent
Presents with epidermal growth factor receptor mutation that stimulates growth pathways nonstop
If it can be diagnosed early, is highly susceptible to specific oncodrugs that inhibit EGFR signaling
- if diagnosed late cant use
Smoking and cancer
Smoking is the cardinal carcinogen associated with lung cancer
- 90% of lung cancers occur in active smokers or people who recently stopped
- near linear correlation between frequency of lung cancer and pain-year cigarette smoking
- 60x more likely in habitual heavy smokers (2 lacks a day for 20years or more)
- stopping smoking helps, but never returns to baseline levels
What is the most common synergistic interaction between carcinogens?
Asbestos and tobacco smoking
- combined is 55x fold increased
- sole asbestos is 5x increased
Genetics and carcinomas of the lung
Mutagenic effect of carcinomas is modified to be greater by hereditary factors
- specifically, polymorphisms in cytochrome P-450 genes have shown to allow increased ability to activate pro carcinogens in cigarette smoke (leads to increased cancer risk)
Morphology of lung carcinoma
All are Typically are firm and gray-white masses
Adenocarcinomas
- located peripherally usually and grow slowly w/ smaller masses
- metastasis very early
- usually grows well-defined acinar patterns or papillary mucinous patters
Squamous cell carcinomas
- located centrally and spread to hilar nodes
- metastasis later
- can show central necrosis patterns and cavitations
- can look well differentiated or poorly differentiated
Small cell lung carcinomas
- located centrally and look grayer than the others
- metastasis to hilar lymph nodes super early, but distally varies
- salt/pepper patterns with crush artifacts present in histology. Also shows necrosis
- always express neuroendocrine markers and can secrete polypeptide hormones
Large cell carcinomas
- very undifferentiated w/ large nuclei and can be central or peripheral
Most common lymph node infected by metals is from lung cancers
Left supraclavicular node (virchow node)
Vena caval syndrome
Carcinomas may compress or infiltrate the superior vena cava which leads to venous congestion
Specifics to apical tumors (pancoast tumors)
Often invade the brachial or cervical plexus which is associated with any of the following:
- severe pain distribution especially along the ulnar nerve
- Horner syndrome
Clinical features associated with lung carcinomas
Symptoms/signs:
- chronic coughing
- expectoration
- chest pain
- SVC syndrome
- pericardial/pleural effusion
- segmental atelectasis
- pneumonitis
- metastasis spread symptoms (hepatomegaly, neurologic issues, bone pain)
Are insidious lesions that spread quickly so often are not respectable before symptoms appear
Prognosis in all types of carcinomas
Squamous cell and adenocarinoma > LCLC > SCLC
Squamous and adenocarcinomas are almost always curable as long as metastasis isnt present
- use of tyrosine kinase and EGFR Inhibtors can help metastasis, but poor prognosis at this point
SCLCs almost always aren’t possible to surgically resection since roughly 99% have metastasis before diagnosis
- very sensitive to chemotherapy, but often come back .
- mean survival is 1 year w/ 5% alive at 10yrs of diagnosis
